Azo dyestuffs



Patented Sept. 17, 1940 MIPATVENTH OFFICE A no DYESTUFES'; H Hugo Schweitzer, Leve kus 6 7 many, assignorto General'Aniline & Film Cor poration, a corporation of Delaware l No Drawing. Application July 21, 1938, Serial N0. 220,501. In Germany July 24, 1 937 6 Claims. (01. 260 166) The present invention relates to new polyazo dyestufis and to a process of preparing the same; more particularly it relates to polyazo dyestufis of the general formula HOaS N112 In this formula A stands for an aromatic radical containing the o-hydroxycarboxylic acid grouping and B and C stand for the residues of aminobenzene or aminonaphthalene being coupled in p-position to the amino group; the radicals B and C may contain sulfonic acid groups, and may be substituted by further radicals as for instance by alkyl radicals, alko-xy radicals and so' My new dyestuffs are obtainable by coupling diazo, compounds of diazo dyestuffs of thegeneral formula wherein A, B and C mean the same as stated above, with monoazo dyestuffs as they are obtained by coupling an aromatic diazo compound containing the o-hydroxycarboxylic acid grouping with 2-amino-5-hydroxynaphthalene-7-sulfonic acid to the side of the amino group i. e., in l-position.

The new dyestuffs which contain at each end of the dyestuff molecule the o-hydroxycarboxylic OOOH acid grouping dye Vegetable fibers in currant to blue shades, which change into currant to grey shades with good fastness to light and washing when after-treated on the fiber with copper salts; the good fastness to washing is especially to be emphasized.

- The following examples illustrate the invention without limiting it thereto, the parts being by weight:

Example 1 15.3 parts of p-aminosalicylic acid are diazotised in the usual manner and coupled with 22.3 parts of 1'-amino-naphthalene-'7su1fonic acid in the presence of sodium acetate. The separated monoazo dyestufi' is then dissolved with 12 parts of anhydrous sodium carbonate, to the solution 70 ccm. of a per cent sodium nitrite solution are added, and the mixture is run at a temperature of 15 C. into a mixture of '75 parts of crude hydrochloric acid and 100 parts of water. When the diazotisation is complete the separated diazo compound is filtered off, washed and, in the presence of parts of sodium acetate, combined with 14.3 parts of l-aminonaphthalene to the diazo dyestufi. After finishing the coupling, the separated dyestui'f is filtered off, washed, dissolved with Water and some caustic soda lye, and further diazotised by adding '70 com. of a 10 per cent sodium nitrite solution and running this solution into a mixture of '75 parts of crude hydrochloric acid and 100 parts of water at a temperature of 0-5 C. The diazo compound filtered off and washed, is combined in a medium alkaline with sodium carbonate with 40.3 parts of the monoazo dyestuli obtained by coupling in an acid medium diazotised p-aminosalicylic acid with 2-amino-5-hydroxynaphthalene7-sulfonic acid.

When the-coupling is complete the dyestuff havin the formula is worked up. It dyes cotton blue shades, which change into grey shades, fast to light and wash-j ing, when after-treated on thefiber with copper salts.

If instead of p-aminosalicylic acid p-aminocresotinic acidor instead of .l-aminonaphthalene-l-sulfonic acid 1-amino-naphthalene-6- sulfonic acid is used, or if in building up the dyestuff the sequence of the 1-aminonaphthalene-6- or -7-sulfonic acid and the l-aminonaphthalene COOH is reversed, dyestufis of similar properties are obtained.

Example 2 27.5 parts of the monoazo dyestufi p -aminosalicylic acid-azo-aniline are diazotised. The separated diazo compound is added to a solution of 20.2 parts of a 3-toluidine-methane-sulfonic acid, containing sodium acetate. When the coupling is complete the dyestuff is filtered ofi. The dyestufi is saponified by boiling it for half an hour with a 25 per cent aqueous sodium hyroxide solution and, when the solution has become cold, the disazo dyestufi is separated by adding hydrochloric acid, washed and dried. Thereupon' is worked up. It dyes cotton currant shades, which change into black-currant shades, fast to light and washing, when after-treated, on the fiber with copper salts. If instead of the toluidine-methanesulfonic acid the aniline-methanesulfonic acid or the 2-toluidine-methanesulfonic acid, or instead of the p-aminosalicylic acid the p-aminocresotinic acid is used, dyestuffs of similar properties are obtained.

Example 3 30 parts of the monoazodyestuff obtained from diazotised p-aminosalicylic acid and 3amino-4- cresol-l-methylether are diazotised in the usual manner. This diazo compound is added to a solution of 24.5 parts of 1-aminonaphthalene-7- sulionic acid, containing sodium acetate. When the coupling is complete the disazodyestufi is isolated, then dissolved with water and some caustic soda lye, and further diazotised by adding ccm. of a 10 per cent sodium nitrite solution and running this solution into a mixture of parts of crude hydrochloric acid and parts of water at atemperature of 510 C. When the diazotisation is complete, the diazo compound is filtered off, washed and combined in a medium alkaline with sodium carbonate with 40.3 parts of the monoazodyestufi obtained by coupling in an acid Q con, 1103s NH: 00011 cm on medium diazotised p-aminosalicyclic acid with 2- amino-5-naphtha1ene-7-su1fonic acid.

When the coupling is complete the dyestufi having the formula SOzH N=N is Worked up. It dyes cotton blue shades which change into grey shades fast to light and washing, when after-treated on the fiber with copper salts.

I claim:

1. As new products the azo dyestufis of the general formula wherein A stands for the radical of an o-hydroxycarboxylic acid of the benzene series, and B and- C stand for radicals of the group consisting of benzene and naphthalene and the alkyl, alkoxy and SO3H substitution products thereof, and

wherein each of the radicals B and C bears the N=N groups attached in p-position to each other, yielding on vegetable fibers currant to blue shades which change, when after-treated with copper salts, into currant to grey shades of good fastness to light and washing.

NH: COOH 2. As new products the azo dyestuffs of the general formula wherein A stands for the radical of an o-hydroxycarboxylic acid of the benzene series, and B and C stand for radicals of the group consisting of naphthalene and sulfonic acids thereof, and wherein each of the radicals B and C bears the -N=N-- groups attached in p-position to each other, yielding on vegetable fibers currant to blue shades which change, when after-treated with copper salts, into currant to grey shades of good fastness to light and washing.

3. As new products the azo dyestuifs of the general formula l\IT=NA HOaS- NHZ' AN=NBN=NC-N=N wherein A stands for the radical of an o-hydroxycarboxylic acid of the benzene series, and B and C stand for radicals of the group consisting of benzene and alkyl, alkoxy and SO3H substitution products thereof, and wherein each of the radicals B and C bears the -N=N- groups attached in p-position to each other, yielding on COOH vegetable fibers currant to blue shades which change, when after-treated with copper salts, into currant to grey shades of good fastness to light and washing.

4. As new products the azo dyestuffs of the general formula wherein A stands for the radical of an o-hydroxycarboxylic acid of the benzene series, one of the middle components B and C stands for a radical of the group consisting of benzene and the alkyl, and the other middle component stands for a alkoxy and SO3H substitution products thereof.

radical of the group consisting of naphthalene and sulfonic acids thereof, and wherein each of dyeing cotton blue shades which change, when after-treated on the fiber with copper salts, into grey shades fast to lightand washing.

6. As new product the azo dyestuff corresponding in the free state to the following formula SOaH dyeing cotton blue shades which change, when after-treated on the fiber with copper'salts, into grey shades fast to light and washing.

HUGO SCHWE'ITZER. 

